Seizures & Epilepsy

Absence seizures
Transient loss of consciousness, with an abrupt onset and termination, unaccompanied
by motor phenomena except for some flickering of the eyelids and minor alteration in
muscle tone. Absences may be typical (petit mal) or atypical and can often be
precipitated by hyperventilation

Myoclonic seizures – Brief, often repetitive, jerking movements of the limbs, neck or trunk
Non-epileptic myoclonic movements are also seen physiologically in hiccoughs
(myoclonus of the diaphragm) or on passing through stage II sleep (sleep myoclonus)

Tonic seizures – Generalized increase in tone

Tonic–clonic seizures
Rhythmical contraction of muscle groups following the tonic phase.
In the rigid tonic phase, children may fall to the ground, sometimes injuring themselves.
They do not breathe and become cyanosed. This is followed by the clonic phase, with
jerking of the limbs. Breathing is irregular, cyanosis persists and saliva may accumulate in
the mouth. There may be biting of the tongue and incontinence of urine. The seizure
usually lasts from a few seconds to minutes, followed by unconsciousness or deep sleep for up to several hours

Atonic seizures
Often combined with a myoclonic jerk, followed by a transient loss of muscle tone
causing a sudden fall to the floor or drop of the head

Focal seizures

Onset in neural network & limited to one cerebral hemisphere

begin in a relatively small group of dysfunctional neurones in
one of the cerebral hemispheres

may be heralded by an aura which reflects the site of origin

may or may not be associated with change in consciousness or more generalised tonic-clonic seizure
Focal seizures